Portable power bank



FIG. 1 is a front perspective view of a portable power bank showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is a rear perspective view thereof; and,

FIG. 9 is a rear perspective view thereof showing that power plug prongs are folded.

The broken lines are shown for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a portable power bank, as shown and described. 